<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
	</head>
	<body>
		<div id="app">
			<input type="text" v-model="num1"/>
			<select v-model="num4" @change="change">
				<option>+</option>
				<option>-</option>
				<option>*</option>
				<option>/</option>
			</select>
			<input type="text" v-model="num2"/>
			<button>=</button>
			<input type="text" v-model="num3"/>
		</div>
	</body>
	<script type="text/javascript">
		var app = Vue.createApp({
			data() {
				return {
					num1:0,
					num2:0,
					num3:0,
					num4:"+"
				}
			},
			 methods:{
				                change(){
				                    if(this.num4 === "+") {
				                        this.num3 = parseInt(this.num1)+ parseInt(this.num2);
				                    } else if(this.num4 === "-") {
				                        this.num3 = this.num1 - this.num2;
				                    } else if(this.num4 === "*") {
				                        this.num3 = this.num1 * this.num2;
				                    } else if(this.num4 === "/"){
				                        this.num3 = parseInt(this.num1) / parseInt(this.num2);
				                    }
				                }
				    },
		});
		var vm = app.mount("#app")
	</script>
</html>
